Sodium formaldehyde sulfoxylate.



" PT FQQ BRUNO RICHARD SEIFERT AND OTTO WILHELM MEVES, OF RADEBEUL, NEAR DRESDEN, GERMANY, ASSIGNORS, BY MESNE ASSIGNMENTS, TO l-IEYDEN CHEMICAL WORKS, OF

NEW YORK, N. Y.

SODIUM FORMALDEHYDE SULFO XYLATE.

Na'saaoso.

Specification of Letters Patent.

Patented May 5, recs.

. jects of the King'of Saxony, and residents of Radebeul, near Dresden, Kingdom of Saxony, German Empire, have invented' a new 4 and useful Improvement in the Manufacture of Sodium Formaldehyde Sulfoxylates, of

a which the following is a specification.

It has been stated that formaldehyde hydrosulfite salts can be produced of any reducing power situated between the reduction of 0.8 gram up to 2.2 grams of indigo by 1 gram 'of formaldehyde hydrosulfite sodium by acting with 1 to 2 e uivalents of sulfurous acid upon a mixture 0 l to 2 equivalents of an aldehyde and 1 equivalent of zinc dust or iron. It is necessary that the quantity of the sulfurous acid be equivalent to the mantity of the aldehyde. Thus, if 2 equiva cuts of formaldehyde are caused to react with 1 equivalent of zinc dust and 2 equivalents of sulfurous acid, the reaction takes place according'to the following equation:

The zinc salt obtained according to equation I, is easily soluble in water, while that obtained according to equation II, is difli .1 cultly soluble. These zinc salts, by asolution i of soda, can be transformed into the sodium salts which can be obtained in dry state by evaporating in vacuo. The sodium salt ob tamed from the zinc salt of equation 11, re-

duces twice the quantity of indigo which is reduced by the sodium salt obtained from the zinc salt of equation I.

If 1% equivalents of S0 and llsequivalents of formaldehyde are caused to react with 1 equivalent of zinc dust, a salt is obtained the above mentioned two. Any quantities of sulfurous acid and formaldehyde lying be tween 1 and 2- equivalents can be caused to act upon 1 equivalent of zinc dust. It is necessary that the quantity of the sulfurous acid be er uivalent to the quantity of the formaldehy e. In this, way, products of a reducing power are obtained lying between the above mentioned limits.

The formaldehyde may be replaced by other aldehydes, for exam le aceta dehyde or benzaldehyde. The pro not of highest decolorizing power is obtained according to the following example:

Example: Into a well stirred mixture of 65 kilos of zinc dust and 80 kilos of a solution of formaldehyde of 40 'sulfurous acid is poured, until the zinc dust has disappeared; about 53 kilos of SO are necessary or this urpose. The reactionv takes place accordmg to the equation:

011,0 Zn so, H2O nocnpsoznon.

The resulting paste of the diflicultly soluble zinc salt is directly ready-for use. It may also be filtered, Washed and dried in vacuo. To obtain the product herein claimed, it is,

however, reacted with soda lye or a solution of sodium carbonate and thus transformed into the corresponding sodium salt which is The solution is ,after t e hot crystalline paste has passed One gram of this'new salt to 2.2 grams of ose crystals, meltthe centrifuge. decolo'rizes from 1.9 up lndlgo. It forms white, 0

whose reducing power lies midway between ing at about 135 to 140 centigrade, soluble In testimony that 'We claim the foregoing in eold water, insoluble in cold and in hot as our invention we have slgned our names in absolute methylalcohol. resenoe of two Witnesses this eighth day of Rat welfllzaiilrni is: If 1 I 1 lovember 1905.

5 orma e y e su oxy ate sodium sa t OH- CH OSON a free of crystal Water, melting at a temperature of about 135 to 140 v centigrade, easily soluble in Water and reduo- Witnesses: ing from 1.9 fold to the 2.2 fold of its Weight PAUL E'. SGHILLING,

10 of indigo, substantially as described. EMIL FEIssLER. 

